Air conditioning, fans, and anything related to keeping it cool, such as insulation. This would include any posts generally discussing how to keep it cool, such as which types of blocks are better insulators.... ideal wall thickness for keeping an A/C house cool, etc.

I only intend to install A/C in one room of my home. I will be using double wall insulation method. I may want to add a second blower to my office. How can I seal the entry door of bedroom? I have not seen any thresholds for doors here.

If by split Unit A/C system you mean the ones where the compressor sits outside the building and the control unit that blows out the cold air is wall mounted within the room, those are the most common type of A/C unit here. The smallest size unit is normally about 9000 BTU which can cool a small room (about 20 sq meters or less). I recommend a slightly larger unit, maybe 13,000 BTU as they can be purchased for only a little bit extra. Installation is almost always included in the price, although there will be a transportation charge if you are located far from the store. Also, extra services + equipment are extra, such as wall mounting the exterior unit, extra thick coolant tubing, etc.

A good 13,000 BTU normally starts at about 20,000 baht at the homepro's, etc. The more bells and whistles, the more expensive.

If your door has a tight seal, you would be normally talking about weatherproofing the lower gap, you can go look in homepro, they offer various solutions.

Remember that a room still needs to breathe otherwise it will get a musty smell (particularly bedrooms). The cooling loss through a small ventilator would be minimal. In cold countries where we have to heat the rooms in the winter, it is the same in reverse.

We are nearing the phase where I get to choose an AirCon. Now comes the BTU calculation.

We have styrofoam wall boards mounted over standard red brick and R-11 batting, over gypsum, in the attic. The roof is CPAC Monier. Not the cheap stuff. The windows are smoke out tinted glass in aluminum frames. 4 windows are approximately 1.5m wide and 1 at 2m wide. The windows will also be shaded with bamboo window screens. I consider my insulation to be better than average for Thailand but below UK or USA standards

The area in question is one room approximately 4.5 x 9.5 meters with a good sealing entry door and an attached bath (no vent blocks).

I have been using 50 sq/m for the online BTU calculators. The average BTU calculation of 4 seperate URL's is 20000 BTU. The maximum being 25000 BTU

All the local suppliers here in Phayao insist I need 36000 BTU. How could there be such a discrepancy in the online calculators and the locals? What is the forum consensus?

BTW the shop technician today told me to estimate 1000 BTU per 800 - 900 sq/m. He also claims this factor has increased over the last 5 years due to climate change,i.e.hotter temps in Thailand. I am no genius but how can hotter temps cause the factor of 1000 per 500 - 600 sq/m to change up 50%? Even in my limited math this does not compute.

If you went into those suppliers shops personally and started asking their advice, they are certainly going to try and talk you into buying more than you need. 18,000 - 25,000 BTU should be more than enough, depending on the height of your ceilings, especially as you have gone to all the trouble of extra insulation.

4x6 m room 13000 std qcon thai const with 1 very shaaded 750 x 1250 window no xtra insul this unit samsung knocks the humidity and temp dow enuf to make room comfy in day wify like thermo at 23c and that feels ok in day i on other hand at night run thermo to min 18c for mossy ctl add 1 zapper unit to catch buggers as the zapper becomes only heat & light source. the wife and 2 cousins at times complain it too cold but all have blankets i am too spoiled with ac

for my build will put 24000 btu on same room size u mention and yes the stores all recc 30k btuh but i just look to knock down humidity and get to 22c day 19c in late night will lay the r11 bat over top suspended cieling as std usa practice and add drapes to windows use natural draft roof as seen in forum pics

Thanks Otis-a. Your 2 cents was invaluable and confirms my research. Will stick with my original plan of 20000 Carrier or York. Carrier mainly because my father spent about 20 years there and we never had anything but Carrier in our homes.

For some more actual experiences, here's what I did for my house in Issan where the hot season temperatures get well above 40°. Some of the insulation is a little better but at least you'll get some ideas. I used double, thin concrete block exterior walls with 2" fiberglass between the walls, Monier roof tiles with foil underneath, good attic ventilation, and 4" of fiberglass batts on the gypsum ceilings . The master bedroom is about 4.5m x 5m with 2 1m x 2m windows and is on the southwest corner of the house with no landscaping shade. I put in a 9K BTU Panasonic unit and it's been more than adequate. I never have to run it on high.

The living room/dining room/kitchen is an interior room that's 5.5m x 9.5m and runs the width of the house. The 5.5m walls are exterior walls but shaded by porches. There's a 3m wide partition wall between the kitchen area and the living room area. I used a 12K BTU unit in the dining area to handle the entire space. Again, it's been more than adequate.

A caveat is that I grew up in hot weather so my wife and I are used to the climate and our normal AC settings are 27° - 28° during the day and 26° in the bedroom at night. If you like it a lot colder than this you might need bigger units.

I was also told to buy a bigger unit than was necessary by a store salesman. In fact it scared my gf to the point where she didnt want to buy A/C as it was too expensive. We were quoted to need a 25,000+ baht + A/C for the master bedroom 4x5m room. <minor edit - 29.10 MGV12>

Since then I have found a Hitachi that is supposed to be super quiet for 17,000 baht. I don't remember how powerful it is but its on the low end of the scale. All I want it for is to reduce the temp to around 23-25c and remove humidity at the same time. Anything over 26C and I don't sleep well. I think this kind of price is more than enough for most people for any bedroom. For larger living rooms I agree a 20,000+ A/C would be better.

The other point is if you go for temperature too low all the time, when ever you go outside would just shock your system with a lot dramatic temp changes. I've heard Australian taxi drivers complain of headaches in summer coz they keep changes between air con and getting out of their cars.

I read an article about acclimatizing to Thai weather and using a minimum amount of A/C is recommended for long stay so you acclimatize better.